1. Field of the Invention
This invention relates to a lighting device, and more particularly to alighting device having a removable cover body and a method for manufacturing the same.
2. Description of the Related Art
Following the evolution of technology, many electronic products progress toward miniaturization and lightweight to facilitate hand carry and use of the same. A microprojector is also a new generation miniaturized portable product. Since the light-emitting diode (LED) is small, and has an energy-saving function and a long service life, it is suitable for use in a light source of the microprojector.
A light source system of the microprojector is an etendue-limited system. Hence, the smaller the etendue of a light source, the higher the use efficiency of light. Further, the etendue is related to the refractive index of a medium which the light rays pass through. The lower the refractive index of the medium, the smaller the etendue. Usually, the refractive index of air is smaller than that of a transparent material, such as glass or optical grade resin. Hence, the etendue of light source which directly emits light to transmit to air is relatively small.
Thus, to develop a lighting device having a small etendue is the current trend.